This invention relates to a heat exchanger which satisfies both the improvement in heat exchange efficiency and the reduction of a flow resistance.
A heat exchanger of the type which is formed by connecting a plurality of cylindrical members each having an increased diameter at an intermediate portion thereof and a reduced diameter at both ends thereof so as to provide a large heat exchange area and in which heat exchange is effected between an internal fluid flowing inside the heat exchanger and an external fluid flowing outside, has been used. In the heat exchanger of this type, a baffle plate is disposed at the increased diameter portion of each cylindrical member, and the internal fluid flowing inside the heat exchanger is so regulated as to flow along the inner wall of the increased diameter portion (intermediate portion) of each cylindrical member in order to improve heat exchange efficiency.
However, because the baffle plates provide a flow resistance to the internal fluid, a pressure loss of the heat exchanger increases. Further, when the whole of the internal fluid is caused to flow along the inner wall of the cylindrical members by the baffle plates, heat exchange is vigorously effected in the cylindrical member on the inlet side of the heat exchanger, while heat exchange on the outlet side is likely to remarkably decrease because the temperature of the internal fluid lowers in the cylindrical member on the outlet side. As a result a non-uniform temperature distribution is likely to develop in the external fluid flowing outside the heat exchanger in a direction crossing the flowing direction of the internal fluid flowing inside the heat exchanger.